%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  7. Auflage
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%%  Beispiel 28-02-5 auf Seite 608.
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%%  Copyright (C) 2016 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{97.16928pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{pst-eucl}
%StopShownPreambleCommands
\begin{document}
\begin{pspicture}(-1,-1)(2.5,2)
  \pstGeonode[PointSymbol=none,
    PosAngle={-45,45,135}]{A}(0,2){B}(2.5,2){C}
  \pspolygon(A)(B)(C)
  \psset{arrows=->,linecolor=red}
  \pstMarkAngle{C}{A}{B}{$\alpha$}
  \pstMarkAngle[MarkAngleRadius=1]{B}{A}{C}{$\alpha$}
  \pstMarkAngle[linestyle=dotted]{B}{C}{A}{$\gamma$}
  \pstMarkAngle[arrowscale=2,MarkAngleRadius=-0.75]{A}{B}{C}{}
\end{pspicture}
\end{document}